>>> On 08.02.19 at 14:44, <nmant...@amazon.de> wrote:
> @@ -33,10 +34,11 @@ unsigned long __read_mostly pdx_group_valid[BITS_TO_LONGS(
>
> bool __mfn_valid(unsigned long mfn)
> {
> - return likely(mfn < max_page) &&
> - likely(!(mfn & pfn_hole_mask)) &&
> - likely(test_bit(pfn_to_pdx(mfn) / PDX_GROUP_COUNT,
> - pdx_group_valid));
> + return evaluate_nospec(
> + likely(mfn < max_page) &&
> + likely(!(mfn & pfn_hole_mask)) &&
> + likely(test_bit(pfn_to_pdx(array_index_nospec(mfn, max_page))
> + / PDX_GROUP_COUNT, pdx_group_valid)));
> }
How about this instead:
bool __mfn_valid(unsigned long mfn)
{
if ( unlikely(evaluate_nospec(mfn >= max_page)) )
return false;
return likely(!(mfn & pfn_hole_mask)) &&
likely(test_bit(pfn_to_pdx(mfn) / PDX_GROUP_COUNT,
pdx_group_valid));
}
Initially I really just wanted to improve the line wrapping (at the
very least the / was misplaced), but I think this variant guards
against all that's needed without even introducing wrapping
headaches.
Jan
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